Aggregation Behavior And Chromonic Liquid Crystal Phase Of A Dye Derived From Naphthalenecarboxylic Acid
Document Type
Article
Publication Date
8-14-2008
Published In
Journal Of Physical Chemistry B
Abstract
Polarizing microscopy, X-ray scattering, and absorption spectroscopy are used to investigate the aggregation process and chromonic liquid crystal of the anionic compound Bordeaux dye, a product of the sulfonation of the dibenzimidazole derivative of naphthalenetetracarboxylic acid. Polarizing microscopy reveals that the liquid crystal phase forms at room temperature when the concentration is only about 6 wt%, a value lower than what is found in many aggregating systems. The X-ray results indicate that the aggregation is via columns, with a cross-sectional area about 2.5 times larger than the individual molecule. Absorption spectroscopy shows a significant change in the absorption spectrum due to aggregation, which is nicely explained by a simple theory of isodesmic aggregation and excitonic coupling between the molecules in an aggregate. The "stacking free energy change" for a molecule in an aggregate relative to a molecule in solution is estimated to be about 9 k(B)T, a larger value than that found in the one other system where it has been estimated.
Recommended Citation
Michelle R. Tomasik , '07 and Peter J. Collings.
(2008).
"Aggregation Behavior And Chromonic Liquid Crystal Phase Of A Dye Derived From Naphthalenecarboxylic Acid".
Journal Of Physical Chemistry B.
Volume 112,
Issue 32.
9883-9889.
DOI: 10.1021/jp803648g
https://works.swarthmore.edu/fac-physics/164
